Manners to arca rail issues. Help needed

Sogan

Sergeant
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Jun 11, 2013
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I’m hoping you guys can help me out here. It appears that I am stacking tolerances with two products: arca rail and manners stock. Both of them, when laid across a level begin to rise up towards the end. If I do nothing with them and just torque them down then I get an arch and a gap between the front action screw and the bipod stud screw area, which is what I am trying to avoid because I would assume that can’t be ideal for accuracy. Here are the two products against a level (I’m using a light to try and make it easier to see in the photos).

The gaps are very obvious in person but the lower quality of photos from uploading them don’t make it as easy to see and downplays the gap some I think.

Here it is with ONLY the front action screw torqued down. The closer I get to 65inch pounds the more the muzzle end wants to rise up:
024C7BA7-7504-40D6-A1A5-65F6A5BA2328.jpeg
Manners PRS2:
873756A9-8301-464B-9CF9-EA0EDE661F87.jpeg
Arca rail:
6283524B-8CCB-469A-9065-D8E3B7F7D57C.jpeg

If I just attach them using the front action screw and the bipod stud I get this arc in the middle(on my phone it shows the gap clear as day but it’s harder to see them when I upload the photos for some reason maybe just because it downgrades the quality?)

AB74E6E7-EA69-400B-B279-9DE7020F2D8F.jpeg


I tried to add a washer to the bipod stud area which at least gives me a consistent gap the whole time but again not sure what is ideal or what I need to do. Here’s the consistent gap with the washer:
13AF4C1F-8916-41DA-9EC0-8FC51AFEF324.jpeg

What’s the hides thoughts on how I need to proceed? Does everyone’s do this or do I have an issue here?
 

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CStroud

Gunny Sergeant
Hessian
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Jun 26, 2018
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Add T- nuts to your stock toward the center of the arca rail to help eliminate the gap.
 

Simia Dei

Boendr
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Feb 11, 2017
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I had the same issue with both of these, not to that extent though. Two extra T nuts solved it and was easy to do as well, did them with the hand drill and a dremel.
B7EA55DA-97D2-4A0A-89B2-6B6795309761.jpeg
 

z28kid

Sergeant
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Jan 3, 2012
345
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Middle TN
I had the same issue, added one t nut in the position closest to the front action screw.
20200504_185252.jpg

I also machined a spacer to fill the gap between the rail and the counterbore where the front action screw goes. I did this to help eliminate warp of the arca rail when front action screw is torqued.
 

b6graham

MMPRL
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Jul 29, 2014
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Not sure why my comment never posted here but I believe I have 4 connections to the stock on my 14" rail
 

tmanners

Sergeant
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Feb 3, 2006
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1232 swift, NKC, MO.
I’m hoping you guys can help me out here. It appears that I am stacking tolerances with two products: arca rail and manners stock. Both of them, when laid across a level begin to rise up towards the end. If I do nothing with them and just torque them down then I get an arch and a gap between the front action screw and the bipod stud screw area, which is what I am trying to avoid because I would assume that can’t be ideal for accuracy. Here are the two products against a level (I’m using a light to try and make it easier to see in the photos).

The gaps are very obvious in person but the lower quality of photos from uploading them don’t make it as easy to see and downplays the gap some I think.

Here it is with ONLY the front action screw torqued down. The closer I get to 65inch pounds the more the muzzle end wants to rise up:

Manners PRS2:

Arca rail:


If I just attach them using the front action screw and the bipod stud I get this arc in the middle(on my phone it shows the gap clear as day but it’s harder to see them when I upload the photos for some reason maybe just because it downgrades the quality?)




I tried to add a washer to the bipod stud area which at least gives me a consistent gap the whole time but again not sure what is ideal or what I need to do. Here’s the consistent gap with the washer:


What’s the hides thoughts on how I need to proceed? Does everyone’s do this or do I have an issue here?
Hi sogan, shoot me a pm with your contact information, I’ll give you a buzz. We do not recommend using a longer than factory speced front action screw to mount a 419 Arca rail on a stock with a mini chassis or any other bottom metal, the reason for this is that you run into a possibility for movement and loss torque specs while shooting. The torque specs on the mini chassis are 65 inch pounds, the front action screw must be seated to the chassis with nothing between the head and the screw cup. The Arca rail will take a ton of abuse while shooting, mostly from the stress of slamming into barricades and the force applied to the stock that is transferred to the rail. During that force we don’t want to see any movement in that rail. Movement in that rail may cause the loosing of the front action screw which will cause torque loss. Once I have a gun setup and torqued I don’t want it changing from shot to shot. When 419 rails are installed at the shop, we mill the rail so the factory minichassis screw will drop thru the rail, then we add xtra screws and t-nuts. Also depending on what model of stock, we actually might add some bedding to make sure the rail is flush to the bottom of the stock. Just about all stocks out there will have a different angle between the bottom of the forend and the angle of the bottom metal area where the front action screw is installed, if that makes sense. If that screw goes thru the rail and is not at a 90degree, it will not fully seat a 100%. Some guys will run the factory screw under the rail, when barreled action is taken out, the screw stays sandwiched between the chassis and rail, nothing is wrong with that, but I would prefer that each time the barreled action is taken out, the front screw is cleaned and oiled before reinstall and touqed. On the new custom mcs-tcs stock 419/mcs tunable weighted Arca rail, the rail actually bolts direct to the chassis about a half inch forward of the front action screw with a 1/4x20 bolt, it takes the force of the rail and transfers it to the chassis direct without affecting the action screws. For guys that need screws and some t-nuts I would be more than happy to shoot them out, just send me a pm. Thank you
 
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Rocketmandb

Gunny Sergeant
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Nov 2, 2018
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On the new custom mcs-tcs stock 419/mcs tunable weighted Arca rail actually bolts direct to the chassis about a half inch forward of the front action screw with a 1/4x20 bolt, it takes the force of the rail and transfers it to the chassis direct without affecting the action screws.
I know this isn't the thread for this, but any update on when the new TCS stocks are going to ship? Anxiously waiting :)
 

Cascade Hemi

Gunny Sergeant
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Feb 9, 2019
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I had to bed my rail to my T4. The stock wasn't flat and I didn't feel like the imparted bend in the rail was a good idea after installing T nuts.
 

rydah

Moons out goons out.
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Minuteman
Feb 12, 2019
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I installed 4 tnuts in total and mines solid. 2-3 wasn’t enough, too much vibration and movement when firing. Could feel it when firing from a loaded bipod.

D0E641C3-5EFD-41E7-99BB-813D52996D2A.jpeg
 

chadrp

Private
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Feb 12, 2017
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Central Iowa
@tmanners or anyone else who may know.

Can an additional t nut be added to a PRS1T stock with gen2 mini chassis at the larger hole (made for the mini chaasis barricade stop i think) in the Area 419 rail just forward of the front action screw without interference with the mini chassis?

I had Manners install the t nuts for my 419 rail, but no t nut was put there and when not using the action screw and my rifle is on my tripod, the rail has a slight flex that could be eliminated with a screw in this location as thats where it balances well on my tripod.
Thanks
 

tmanners

Sergeant
Belligerents
Feb 3, 2006
485
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1232 swift, NKC, MO.
@tmanners or anyone else who may know.

Can an additional t nut be added to a PRS1T stock with gen2 mini chassis at the larger hole (made for the mini chaasis barricade stop i think) in the Area 419 rail just forward of the front action screw without interference with the mini chassis?

I had Manners install the t nuts for my 419 rail, but no t nut was put there and when not using the action screw and my rifle is on my tripod, the rail has a slight flex that could be eliminated with a screw in this location as thats where it balances well on my tripod.
Thanks
Hi Chadrp, Yes no problem on adding t-nuts in the stock. Also if iam understanding you correctly, yes on bolting the rail to the barricade attachment hole on the gen2 barricade mini chassis. That is a very solid and stable location. At that location, it will transfer all the stress to the chassis but not the action screw mounting locations. I would need to see what version of 419 rail you have, I know that they have a version just for the gen2 barricade mini chassis. Shoot me pm, I will give you a buzz, I can get you fixed up no matter what version you are running. Thank you
 
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chadrp

Private
Belligerents
Feb 12, 2017
316
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34
Central Iowa
Hi Chadrp, Yes no problem on adding t-nuts in the stock. Also if iam understanding you correctly, yes on bolting the rail to the barricade attachment hole on the gen2 barricade mini chassis. That is a very solid and stable location. At that location, it will transfer all the stress to the chassis but not the action screw mounting locations. I would need to see what version of 419 rail you have, I know that they have a version just for the gen2 barricade mini chassis. Shoot me pm, I will give you a buzz, I can get you fixed up no matter what version you are running. Thank you
Pm sent Thanks!